Firearm safety mechanism

Abstract

A firearm safety mechanism includes a lock with engagement structure. The engagement structure has a locked position in which the engagement structure operatively engages a portion of the firing mechanism to prevent discharge of the firearm. The engagement structure also has an unlocked position permitting operation of the firing mechanism. The lock includes selection structure permitting movement of the engagement structure from the locked position to the unlocked position upon the reception of a predetermined selection criteria. The firearm can be locked against unauthorized use and unlocked by an authorized user without resort to external accessories.

I claim: 
     
       1. A firearm safety lock, comprising: combination entering means accessible from the exterior of the weapon;   an engagement portion movable between a locked position in which the engagement portion operatively engages a movable portion of the firing mechanism to prevent discharge of the firearm, and an unlocked position permitting operation of the firearm;   at least one lock member disposed between the combination entering means and the engagement portion, the lock member being adapted to prevent movement of the engagement portion from the locked position to the unlocked position, the lock member being movable to a position where movement of the engagement portion to the unlocked position is permitted, and comprising at least one sprocket having a plurality of sprocket teeth, said combination entering means being adapted to engage said sprocket to cause rotation thereof, the engagement portion comprising at least one protrusion adjacent to each sprocket, each sprocket having channel means, movement of said sprocket by said combination entering means a predetermined number of times aligning said channel means with said protrusions, whereby said protrusions can be moved into said channel means and said engagement portion can be moved from the locked position to the unlocked position.   
     
     
       2. The firearm safety lock of claim 1, wherein said channel means are provided in a channel disk, one channel disk affixed to each sprocket. 
     
     
       3. The firearm safety lock of claim 2, wherein the channel disks are moveable with respect to said sprockets, whereby a relative position of the channel means to the sprocket can be varied to alter the number of operations of the combination entering means necessary to align the channel means with the protrusions. 
     
     
       4. The firearm safety lock of claim 1, wherein the combination entering means comprise push rods, one of said push rods being associated with each sprocket, operation of the push rods being adapted to rotate the sprocket. 
     
     
       5. The firearm safety lock of claim 4, further comprising means for biasing said sprockets for rotation about an axis, and ratchet means, said ratchet means being adapted to engage said sprocket teeth to prevent rotation of said sprockets under the influence of said biasing means, and ratchet biasing means adapted to bias said ratchet members into engagement with said sprocket teeth. 
     
     
       6. The firearm safety lock of claim 5, further comprising reset means, the reset means being adapted to move said push rods and said ratchet members from contact with said sprocket means, whereby rotation of said sprockets by said sprocket biasing means will be substantially unimpeded, and stop means on said sprocket and a stop surface on said firearm, said stop means on said sprocket being adapted to engage the stop surface on said firearm to halt rotation of said sprockets at a predetermined starting position. 
     
     
       7. The firearm safety lock of claim 6, wherein said reset means comprises a reset slide member being slidably mounted adjacent to said ratchet members and said push rods, said reset slide member having a plurality of cam pins, whereby movement of said reset slide will cause movement of said cam pins into contact with said push rods and said ratchet members to disengage said push rods and said ratchet members from contact with said sprocket teeth. 
     
     
       8. The firearm safety lock of claim 7, wherein said push rods have hinge means permitting movement of a portion of said push rods with contact by said cam pin. 
     
     
       9. The firearm safety lock of claim 6, wherein said engagement portion comprises a locking bar, said locking bar being adapted to abut a portion of the firing mechanism which must move to fire the weapon, thereby preventing operation of the firearm. 
     
     
       10. A firearm safety lock for attachment to exterior surfaces of firearms having an external safety mechanism moveable between at least "safe" and "unsafe" positions for preventing and enabling, respectively, operation of the firearm, said firearm safety lock comprising; a housing, and means for attaching the housing to said firearm so as to be external to said firearm upon installation;   a lock opening device external to said firearm upon installation and assessable from the exterior of the housing;   an engagement portion external to said firearm upon installation, said engagement portion extending through the housing and being positionable between a locked position in which the engagement portion operatively engages said external safety mechanism to prevent movement of said safety mechanism to said "unsafe" position, and to thereby prevent discharge of the firearm, and an unlocked position permitting said safety mechanism to be moved to said "unsafe" position and thereby operation of the firearm; and,   lock means within said housing and external to said firearm upon installation, said lock means being operatively disposed between said lock opening device and said engagement portion, the lock means being adapted to selectively permit and prevent movement of the engagement portion between the locked and unlocked positions, said lock means being adapted to permit movement of said engagement portion to said unlocked position upon proper operation of said lock opening device.   
     
     
       11. The firearm safety lock of claim 10, wherein said lock means is a combination lock, and said lock opening device comprises combination entering means, whereby operation of said external safety mechanism will be restricted to users having an appropriate combination. 
     
     
       12. The firearm safety lock of claim 11, wherein said lock member comprises a sprocket having a plurality of sprocket teeth, said combination entering means being adapted to engage said sprocket to cause rotation thereof. 
     
     
       13. The firearm safety lock of claim 12, wherein the engagement portion comprises at least one protrusion adjacent to each sprocket, each sprocket having channel means formed in an exterior surface of said sprocket, movement of said sprocket by said combination entering means a predetermined number of times aligning said channel means with said protrusions, whereby said protrusions can be moved into said channel means and said engagement portion can be moved from the locked position to the unlocked position. 
     
     
       14. The firearm safety lock of claim 13, wherein said channel means are provided in a channel disk, one channel disk being affixed to each sprocket. 
     
     
       15. The firearm safety lock of claim 14, wherein the channel disks are movable with respect to said sprockets, whereby a relative position of the channel means to the sprocket can be varied to alter the number of operations of the combination entering means necessary to align the channel means with the protrusions. 
     
     
       16. The firearm safety lock of claim 13, wherein the combination entering means comprise push rods, one of said push rods being associated with each sprocket, operation of the push rods being adapted to rotate the sprocket. 
     
     
       17. The firearm safety lock of claim 16, further comprising means for biasing said sprockets for rotation about an axis, and ratchet means, said ratchet means being adapted to engage said sprocket teeth to prevent rotation of said sprockets under the influence of said biasing means, and ratchet biasing means adapted to bias said ratchet members into engagement with said sprocket teeth. 
     
     
       18. The firearm safety lock of claim 17, further comprising reset means, the reset means being adapted to move said push rods and said ratchet members from contact with said sprocket means, whereby rotation of said sprockets by said sprocket biasing means will be substantially unimpeded, and further comprising stop means on said sprocket and a stop surface on said firearm, said stop means on said sprocket being adapted to engage the stop surface on said firearm to halt rotation of said sprockets at a predetermined starting position. 
     
     
       19. The firearm safety lock of claim 18, wherein said reset means comprises a reset slide member being slidably mounted adjacent to said ratchet members and said push rods, said reset slide member having a plurality of cam pins, whereby movement of said reset slide will cause movement of said cam pins into contact with said push rods and said ratchet members to disengage said push rods and said ratchet members from contact with said sprocket teeth. 
     
     
       20. The firearm safety lock of claim 19, wherein said push rods have hinge means permitting movement of a portion of said push rods when contacted by said cam pin. 
     
     
       21. The firearm safety lock of claim 18, wherein said engagement portion comprises a locking bar, said locking bar being adapted to abut a portion of the firing mechanism which must move to fire the weapon, thereby preventing operation of the firearm. 
     
     
       22. The firearm safety lock of claim 11, further comprising reset means adapted to return said combination lock means to a predetermined starting position.